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Originally published In Press as doi:10.1074/jbc.M906232199 on March 16, 2000
J. Biol. Chem., Vol. 275, Issue 21, 15876-15884, May 26, 2000
L-Selectin Signaling of Neutrophil Adhesion and Degranulation
Involves p38 Mitogen-activated Protein Kinase*
James E.
Smolen §,
Thomas K.
Petersen¶,
Cody
Koch ,
Stephen J.
O'Keefe ,
William A.
Hanlon ,
Scott
Seo ,
David
Pearson**,
Milligan C.
Fossett , and
Scott I.
Simon**
From the Department of Pediatrics, Leukocyte Biology
Section, Baylor College of Medicine, Houston, Texas 77030-2600, the
¶ Department of Clinical Studies, Central Laboratory, The Royal
Veterinary and Agricultural University, DK-1870 Frederiksberg C,
Copenhagen, Denmark, the Department of Immunology and
Rheumatology, Merck Research Laboratories, Rahway, New Jersey 07065, and ** Biomedical Engineering, University of California,
Davis, California 95616-5294
Received for publication, August 4, 1999, and in revised form, March 2, 2000
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ABSTRACT |
The adhesion molecules known as selectins mediate
the capture of neutrophils from the bloodstream. We have previously
reported that ligation and cross-linking of L-selectin on the
neutrophil surface enhances the adhesive function of
2-integrins in a synergistic manner with
chemotactic agonists. In this work, we examined degranulation and
adhesion of neutrophils in response to cross-linking of L-selectin and
addition of interleukin-8. Cross-linking of L-selectin induced priming
of degranulation that was similar to that observed with the alkaloid
cytochalasin B. Activation mediated by L-selectin of neutrophil shape
change and adhesion through CD11b/CD18 were strongly blocked by Merck
C, an imidazole-based inhibitor of p38 mitogen-activated protein kinase
(MAPK), but not by a structurally similar non-binding regioisomer.
Priming by L-selectin of the release of secondary, tertiary, and
secretory, but not primary, granules was blocked by inhibition of p38
MAPK. Peak phosphorylation of p38 MAPK was observed within 1 min of
cross-linking L-selectin, whereas phosphorylation of ERK1/2 was highest
at 10 min. Phosphorylation of p38 MAPK, but not ERK1/2, was inhibited
by Merck C. These data suggest that signal transduction as a
result of clustering L-selectin utilizes p38 MAPK to effect neutrophil
shape change, integrin activation, and the release of secondary,
tertiary, and secretory granules.
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INTRODUCTION |
Neutrophils circulate in the vasculature in a passive state and
become more adhesive upon stimulation at sites of inflammation. Margination to the vessel wall and subsequent transmigration and phagocytosis (1) requires a number of surface proteins, including the
2-integrins and the selectins, as mediators of adherence to the endothelium (2-5). A sequence of molecular and biophysical events has been identified that facilitates neutrophil activation and
increased adherence during the acute inflammatory response in
vivo. Neutrophils entering post-capillary venules adjacent to
inflammatory foci develop transient rolling adhesive interactions with
endothelium via selectins (6). Following exposure to inflammatory cytokines such as tumor necrosis factor and interleukin-1, endothelial cells are induced to express E-selectin and P-selectin (6). Several
surface glycoproteins on neutrophils, including L-selectin and
P-selectin glycoprotein ligand 1, present oligosaccharide moieties that
serve as counter receptors for E-selectin and P-selectin. In
conjunction with neutrophil membrane L-selectin, which recognizes oligosaccharides on endothelial cells, they promote tethering and
rolling of neutrophils on endothelium under flow conditions (3, 6, 7).
Following ligation, all three selectins have demonstrated the ability
to signal into the cell (8).
Neutrophil rolling is a prerequisite for the transition to a
shear-resistant firm adhesion on the endothelium (2-4, 7). Neutrophil
arrest is mediated by the 2-integrins whose expression level and avidity for ligands are increased by the binding of chemotactic receptors early in the process of emigration (3). For
example, the adhesivity through binding of Mac-1 (CD11b/CD18) and LFA-1
(CD11a/CD18) to ICAM-11
(CD54) is increased by exposure of neutrophils to numerous chemotactic stimuli, including IL-8, which is synthesized and presented on the
surface of inflamed endothelium (4, 6). During neutrophil activation,
L-selectin, which initially has a high basal expression, is shed while
Mac-1 is increased 10-20-fold on the surface following mobilization of
granule stores (5). These changes in surface expression and affinity
occur over seconds to minutes following stimulation (9).
Once migrated to the site of tissue injury, the neutrophil's chief
function becomes that of a secretory cell. In response to the ligation
of L-selectin or chemotactic receptors, CD11b/CD18 is up-regulated from
rapidly mobilized secretory granules (10-13). Increasing intensity of
stimulation results in the release of secondary (specific) and then
primary (azurophil) granules, a process known as sequential
degranulation (14, 15). To a large extent, the extracellular release of
specific and azurophil granules remains under separate control
(14-17). Chemoattractants and other substances selectively elicit the
release of specific granules under conditions wherein azurophilic
granule enzymes are not discharged (16, 18, 19). On the other hand,
stimuli for azurophilic granule release also stimulate concomitant
exocytosis of specific granules (20), with rare exceptions (17). The
resistance of azurophil granules to secretion may be due to a
requirement for a biochemical signal in addition to Ca2+
(21).
There is evidence that adhesion supported by 2-integrins
or selectins can sensitize neutrophils for superoxide generation (22-24). In this regard, cross-linking of L-selectin or Mac-1 with monoclonal antibody results in secretion of tertiary, but not primary,
granules (25). Clustering of integrins and selectins triggers
intracellular signals, including intracellular Ca2+ release
and phosphorylation of several cytoplasmic tyrosine kinases (26-28).
Published data indicate that some elements of a signaling pathway
involving the mitogen-activated protein kinases (MAPK) are involved in
signaling through both L-selectin and Mac-1 (28-30). However, to date
there are no data linking the processes of adhesion and degranulation
to signaling events involving p38 MAPK in neutrophils.
In previous studies, we examined how concurrent signaling through
chemotactic factors and L-selectin affected adhesive function (31-33).
We showed that cross-linking of L-selectin, in the presence of IL-8,
potentiated adhesion of Mac-1 and LFA-1 to ICAM-1 under physiologic
conditions of shear flow (33). Subsequent transmigration on IL-1
stimulated human umbilical vein endothelial cells was also potentiated
by L-selectin cross-linking (31, 32). In the current study, our
objective was to determine whether L-selectin could influence the
secretory functions of neutrophils. We examined whether
antibody-induced clustering of L-selectin could potentiate the extent
of degranulation in response to chemotactic stimulation. We show that
cross-linking of L-selectin leads directly to phosphorylation of p38
MAPK. This response preceded activation of adhesion and priming of
degranulation. Like shape change and activation of adhesion,
L-selectin-mediated priming for secretion of secondary and tertiary
granules was blocked by an inhibitor of p38 MAPK.
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EXPERIMENTAL PROCEDURES |
Agonists, Inhibitors, and Antibodies--
IL-8 was obtained from
R&D Systems (Minneapolis, MN). Specific inhibitors of p38 MAPK were
synthesized by Merck Research Laboratories (Westpoint, PA). Merck C is
a high affinity p38 inhibitor
((S)-5-[2-(1-phenylethylamino)pyrimidin-4-yl]-1-methyl-4-(3-trifluoromethylphenyl)-2-(4-piperidinyl)imidazole). Merck A is an inactive regioisomer used as a control compound ((S)-4-[2-(1-phenylethylamino)pyrimidin-4-yl]-1-methyl-5-(3-trifluoromethylphenyl)-2-(4-piperidinyl)imidazole). These inhibitors were stored in dimethyl sulfoxide and diluted at least
10,000-fold in buffer for treatment of cells. HuDreg55 and HuDreg200
are human IgG4 anti-L-selectin monoclonal antibodies that
were generously provided by Dr. Ellen Berg from Protein Design Labs
(Mountain View, CA). fMLP and cytochalasin B were purchased from Sigma.
A humanized IgG form of a blocking anti-CD11b mAb, Hu60.1 was kindly
supplied by Laura Whitehouse of Repligen Corp. (Cambridge, MA). All
mAbs were titrated by flow cytometry to determine saturating
concentrations. Fluorescein-labeled and unlabeled goat anti-human and
mouse IgG (H+L) F(ab')2 fragments and for cross-linking primary monoclonal antibodies bound to the neutrophil surface were
purchased from Kirkegaard & Perry Laboratories, Inc. (Gaithersburg, MD).
Isolation of Neutrophils--
Human peripheral blood neutrophils
were obtained from healthy, adult donors by collection into sterile
syringes with 10 units/ml heparin (Elkins-Sinn Inc., Cherry Hill, NJ).
Neutrophils were isolated using a one-step method in which blood was
centrifuged through a Ficoll-Hypaque density gradient (Mono-Poly
Resolving Medium; ICN Pharmaceuticals Inc., Costa Mesa, CA) as
described previously (32). Cells were washed and resuspended in HEPES buffer (10 mM KCl, 110 mM NaCl, 10 mM glucose, 1 mM MgCl2, 30 mM HEPES, pH 7.4) containing 0.1% human serum albumin
(HSA; Armour Pharmaceutical Co., Kankanee, IL). Isolated neutrophils
were diluted to the desired concentration in HEPES buffer containing
0.1% HSA, 1.5 mM CaCl2 before each experiment,
and kept at room temperature for 1 h before use. Greater than 95%
of the isolated cells were polymorphonuclear leukocytes, and viability
was found to be >99% by trypan blue exclusion.
Flow Cytometric Detection of Adhesion Receptor
Expression--
The expression of CD11b/CD18 was detected by flow
cytometry using 2LPM19cPE as described previously (34). Neutrophils
(106/ml) were incubated with 10 µg/ml primary mAb in
HEPES buffer, 0.1% HSA at 37 °C for 10 min, excess antibody was
washed out, and samples were read on a FACScan flow cytometer on linear
amplifier settings (Becton Dickinson Inc., San Jose, CA). Cross-linking of L-selectin was performed by preincubating cells with the combination of HuDreg55 and HuDreg200 at 10 µg/ml for 7 min. For kinase
inhibition, cells were preincubated in the presence or absence of 3-10
nM (as denoted) Merck A or Merck C at 37 °C for 45 min
before activating cells by cross-linking L-selectin.
Flow Cytometric Detection of Mac-1 Adhesivity (Bead
Binding)--
Carboxylated fluorescent latex beads (diameter = 2 µm; Molecular Probes, Inc., Eugene OR) were washed three times with
Dulbecco's phosphate-buffered saline (Life Technologies) and incubated
in HEPES buffer, 0.1% HSA at 37 °C for 45 min in order to coat them with albumin, a ligand for adhesion through CD11b/CD18 (35). Beads were
then dispersed by sonication and counted before use. Neutrophils
(5 × 105) were mixed with 1 × 107
albumin-coated beads, 0.04 µg/ml LDS-751 (Molecular Probes, Inc., Eugene OR; a red nucleic acid dye used to identify neutrophils) in a
final volume of 0.5 ml of HEPES buffer, 0.1% HSA, 1.5 mM CaCl2 in a mixing tube containing a small magnetic stir
bar. The sample was then placed for 2 min in a specially designed
37 °C mixing chamber as described previously (34, 36). L-Selectin was cross-linked by pretreatment with HuDREG200 and subsequent activation by addition of goat anti-human F(ab')2 as
described above in the presence and absence of co-stimulation with IL-8 (1 nM). Cell suspensions and beads were then sheared in the
test tube at a rate of rotation of ~300 rpm corresponding to shear stresses estimated at <1.0 dyn/cm2 (36). The mixing
assembly of magnetic stirrer and test tube were then fitted in-line to
the sample inlet of a FACScan flow cytometer to measure the kinetics of
neutrophil-bead adhesion in real time with the detection methods as
described previously (34). Neutrophils bound between one and six beads
dependent on activation of CD11b/CD18 and the level of binding was
proportional to the extent of cell activation as described previously
(32, 34). Gating on the non-adherent single neutrophil population and
each distinct population of neutrophil-bead conjugates enabled computation of the mean number of beads/neutrophil (32). Data are
presented as the mean number of beads bound per neutrophil relative to
the number bound by unstimulated sheared suspensions (e.g.
typically 1 bead bound per 2 neutrophils).
Analysis of p38 MAP Kinase, ERK1/2, and MAPK-activated Protein
Kinase--
Neutrophils (5 × 106/ml) were
preincubated with Merck A or Merck C (10 nM) or left
untreated for 45 min at 37 °C and stimulated in the presence of
HuDreg200 and HuDREG55 together at 10 µg/ml for between 1 and 10 min.
After the indicated incubation, the reaction mixture was quickly
centrifuged and the supernatant removed by aspiration. The cell pellet
was rapidly frozen in liquid nitrogen and suspended in 60 µl of
ice-cold lysis buffer (50 mM HEPES, pH 7.5, 1% Triton
X-100, 2 mM sodium orthovanadate, 100 mM sodium fluoride, 1 mM EGTA, and CompleteTM protease
inhibitor mixture, 2 times (Roche Molecular Biochemicals, Indianapolis,
IN)). After slow thaw at 4 °C for 60 min, the lysate was centrifuged
at 15,000 × g for 15 min. The supernatant (50 µl)
was added to 50 µl of sample buffer (62.5 mM Tris-HCl, pH 6.8, 25% glycerol, 2% SDS, 5% 2-mercaptoethanol, and 0.01%
bromphenol blue), boiled for 5 min at 100 °C, and stored at
80 °C. Aliquots (15 µl) were resolved using 12% discontinuous
SDS-polyacrylamide gels, according to the method of Laemmli (37).
Protein electroblotting was performed according to the method of Towbin
et al. (38). Protein transfer onto 0.45-µm HybondTM
ECLTM nitrocellulose membranes (Amersham Pharmacia Biotech,
Piscataway, NJ) was performed using chilled transfer buffer (25 mM Trizma (Tris base), 192 mM glycine, and 20%
methanol) at 100 V, 250/350 mA for 1 h at 4 °C. Immediately after protein transfer, nitrocellulose membranes (blots) were placed
into TBST buffer (Tris-buffered saline, pH 7.6, 0.1% Tween 20)
containing 5% nonfat dry milk for 1 h at 25 °C. The blots were
washed three times for 5 min each with 15 ml of TBST and incubated
overnight at 4 °C with primary antibody, diluted 1:5,000 in 10 ml of
TBST. PhosphoPlusTM (New England Biolabs Inc., Beverly MA)
antibodies detected the dually phosphorylated forms of p38 MAPK on
Thr180/Tyr182 and ERK1/2 (p44/42 MAP kinase) on
Thr202/Tyr204. Finally, the blots were washed
three times for 5 min each with 15 ml of TBST and incubated for 1 h at 25 °C with anti-rabbit secondary antibody conjugated to
horseradish peroxidase, diluted 1:5,000 in 10 ml of TBST.
Chemiluminescent detection was performed using LumiGLOTM
reagent (Kirkegaard & Perry Laboratories) and peroxide.
MAP kinase activity was determined on whole cell lysates from
neutrophils prepared as described above. Suspensions of neutrophils (5 × 106 cells) were preincubated for 45 min at
37 °C in the absence and presence of Merck A or Merck C (5 nM). Cells were then stimulated with HuDreg200 and HuDREG55
together at 10 µg/ml for 3 min at 37 °C. The cell lysates were
diluted 10-fold in lysis buffer and a 21-µl aliquot was mixed with 3 µl of 250 mM HEPES, pH 7.6, 200 mM
MgCl2, 1 mM Na3VO4, 20 mM dithiothreitol, 200 mM -glycerol phosphate, and 50 mM sodium fluoride buffer. To this were
added 6 µl of 125 µg/ml recombinant human hsp27 (StressGen
Biotechnologies, Victoria Canada), 100 µM ATP, and 1 mCi/ml [ -33P]ATP. The reaction mixture was mixed
gently and incubated at ambient temperature for 30 min. The reaction
was stopped by adding 15 µl of 3× SDS-PAGE gel sample buffer to the
reaction and boiling for 3 min. Phosphorylated hsp27 was resolved by
SDS-PAGE (12%) and the gel dried and subjected to PhosphorImager
analysis for quantitation.
Neutrophil Shape Change--
Neutrophils (106/ml)
were preincubated with Merck compounds at concentrations ranging from
0.01 to 100 nM for 45 min at 37 °C in buffer with
Ca2+ added. Cells were stimulated by cross-linking of
L-selectin by preincubating cells with 10 µg/ml primary mAb, washing
out excess, and cross-linking with goat anti-human F(ab')2
IgG (H+L) for an additional 7 min. Cell samples were then fixed in an
equal volume of 2% glutaraldehyde in phosphate-buffered saline.
Neutrophil morphology was assessed under a phase-contrast microscope. A
total of 100 cells in each sample were scored on a scale of 1 to 4 using the following shape change scores: 1, spherical cells were round with no extensions on the plasma membrane; 2, ruffled cells remained round with minimal extensive ruffling of the plasma membrane; 3, bipolar cells had a leading edge with clearly extended pseudopod; 4, uropod cells had a pseudopod that defined the leading edge and a well
formed rounded tail (uropod) (31). A mean shape change index (M) was
calculated for each intervention by summing the shapes of 100 cells
observed displaying a morphology s by the following
equation.
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(Eq. 1)
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A mean shape change of 4 was observed with stimulation by
chemotactic factor (IL-8 0.5 nM) and mean shape
change of 2 following cross-linking with L-selectin. Neutrophils were
preincubated with Merck compounds and subsequently activated by
cross-linking L-selectin.
Degranulation of Neutrophils and Cell Viability--
Neutrophils
(5 × 106 cells/ml) were treated with 10 µg/ml
HuDreg55 and HuDreg200 (which bind to distinct epitopes and effectively cross-link L-selectin) for 10 min at room temperature. For inhibitor studies, cells were preincubated in the presence or absence of Merck A
or Merck C at various concentrations at room temperature for 45 min.
The cell suspensions were then stimulated with various concentrations
of IL-8 for 5 min at 37 °C. Degranulation assays were conducted as
described previously (39). In essence, aliquots of the cell suspensions
were chilled on ice and were then centrifuged at 750 × g for 10 min. Aliquots of the supernatants were taken for
standard determinations of -glucuronidase (40) and myeloperoxidase (41) (enzymes found exclusively in azurophil granules) and lactoferrin (42, 43) (a component of specific granules). Cells were also taken for
determinations of cell surface expression of Mac-1 (34), which is found
in the membranes of specific and tertiary granules of resting cells
(10-13). The activity of the total granule contents of the cells was
based on a lysed (0.1% Triton X-100 for 5 min at 37 °C) cell
supernatants. Degranulation in response to stimuli was calculated as % release of total granular contents. All experiments were performed in duplicate.
-Glucuronidase activity was measured in the supernatants using
phenolphthalein glucuronic acid as substrate (40). Reaction was stopped
by addition of glycine buffer, pH 10.0, and the absorbance was measured
at 540 nm. Myeloperoxidase activity was assayed by using hydrogen
peroxide and o-dianisidine dihydrochloride (Sigma) as
substrate (41). Light extinction was measured at 560 nm after 10 min
incubation at room temperature. Lactoferrin was measured using an
indirect enzyme-linked immunosorbent assay (42). Polystyrene microtiter
plates (Corning) were incubated with goat anti-human lactoferrin
(Nordic Immunological Products) as a capture antibody. The plate was
washed, and incubated with 1% bovine serum albumin (Sigma) blocking
buffer for 1 h. Samples or standard human lactoferrin (Calbiochem)
in Dulbecco's phosphate-buffered saline were then allowed to interact
with the capture antibody. Following washing, the plate was incubated
with rabbit anti-human lactoferrin antibody (Cappel) for 1 h.
Subsequently, the plate was washed and incubated overnight at 4 °C
with goat anti-rabbit antibody (ICN Pharmaceuticals Inc., Costa Mesa,
CA) conjugated with peroxidase. Following plate washing,
o-phenylenediamine dihydrochloride substrate was added and
the plates were developed at room temperature. Development was stopped
by addition of H2SO4 and absorbance at 490 nm
was read in an enzyme-linked immunosorbent assay well reader. The unknown concentrations were then determined by interpolating from a
standard curve.
Viability of the cells was measured in three ways: 1) trypan blue
exclusion; 2) release of lactate dehydrogenase (44); and 3) a LIVE/DEAD
flow cytometric viability/cytotoxicity kit using the methods provided
with the kit (Molecular Probes, Eugene, OR). Dead cells monitored by
flow cytometry were consistently 4-8% in untreated control samples.
Similarly, lactate dehydrogenase release ranged from 4 to 6% in
untreated controls. For all three techniques, viability was not altered
by Merck C or Merck A at concentrations up to 50 nM.
Statistical Analysis--
Data were collected for separate
conditions in each experiment and results are presented as mean ± S.E. For routine comparisons between conditions, a one-way analysis of
variance (ANOVA) was performed using GraphPad Software PRISM, San
Diego, CA. The probability of statistical significance between two
interventions was determined by the Student-Newman-Keuls test. The
paired Student test was used for some binary comparisons and for
comparisons to control conditions in dose-response curves (as noted).
Probability values p < 0.05 were considered significant.
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RESULTS |
In previous studies, we examined the process of chemotactic
signaling on 2-integrin adhesive function (31-33). We
reported that cross-linking of L-selectin and addition of PAF or IL-8
were synergistic in activation of resting neutrophils. Here we examined the release of primary, secondary, and tertiary granules from neutrophils in response to cross-linking of L-selectin and addition of
IL-8.
We first wished to determine if ligation of L-selectin could serve as a
sensitizing agent for degranulation. Since CD11b/CD18 is contained in
secondary, tertiary, and secretory granules in neutrophils (10-13),
the surface expression of the integrin should be enhanced if these
labile pools are mobilized. In experiments not shown, we first
determined that cross-linking of L-selectin enhanced degranulation
induced by IL-8. We performed extensive dose-response studies with IL-8
and selected a concentration of 1 nM as optimal for further studies.
As shown in Fig. 1A, surface
expression of Mac-1 was statistically greater than unstimulated control
at 1 nM IL-8. Of greatest interest here is the observation
that cross-linking of L-selectin, by treatment with two humanized
antibodies that bind to distinct epitopes on the lectin domain
(HuDREG200 and HuDREG55), also enhanced the display of Mac-1 (Fig.
1A). That is, background levels in the absence of IL-8 were
significantly greater with cross-linking of L-selectin alone. Also,
with cross-linking of L-selectin, the responses elicited by IL-8 were
significantly greater than unstimulated levels.

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Fig. 1.
Neutrophils are sensitized for degranulation
by cross-linking of L-selectin prior to IL-8 stimulation.
Neutrophil degranulation was induced by addition of 1 nM
IL-8 and/or L-selectin cross-linking (10 µg/ml HuDreg55 and
HuDreg200). Degranulation was characterized by measurement of: Mac-1
(CD11b/CD18) expression (n = 11) plotted as mean
fluorescence intensity ± S.E.; lactoferrin (n = 9); MPO (n = 9); and -glucuronidase
(n = 11). The latter three parameters are expressed as
% release of total content in lysed neutrophils, mean ± S.E. A
paired ANOVA was used to compare across treatments with "#"
denoting a p value of <0.05 versus the control
(no treatment). A paired t test was used to test whether a
treatment increased degranulation compared with the no treatment
control with a p value of <0.05 denoted by "*". In
addition, for p < 0.01 comparisons are denoted by
"##" or "**" and tripled marks indicate p < 0.002.
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As Mac-1 is found in secondary, tertiary, and secretory granules, its
expression at these low concentrations of agonist should reflect only
the elaboration of the tertiary and secretory granules, the more labile
of the pools (10-13). To examine secondary granules in this process,
we measured lactoferrin in the cell supernatants (Fig. 1B).
In the absence of any other condition, only a small amount of
lactoferrin was released in response to IL-8. In contrast, cross-linking of L-selectin alone and in combination with 1 nM IL-8 produced significant release of lactoferrin.
The granule type most resistant to release is the azurophil, from which
we measured both myeloperoxidase (MPO) and -glucuronidase. As can be
seen in Fig. 1C, release of MPO was not statistically significant except in the strongest stimulatory conditions of IL-8 plus
cross-linking. Similar results were found with -glucuronidase release (Fig. 1D), with the exception of a statistically
significant enhancement of degranulation induced by 1 nM
IL-8 alone. Taken together, the data show that IL-8 is a weak inducer
of degranulation (at these relatively low concentrations), but its
effect is significantly enhanced by co-stimulation with L-selectin.
We confirmed that cross-linking of L-selectin enhanced adhesive
function. This was measured as an increase in the binding of
albumin-coated latex beads to neutrophils, a process that is dependent
on the activation of Mac-1 (Fig. 2).
Unstimulated neutrophils sheared in suspension with beads did not
increase their adhesiveness over time. In response to stimulation with
IL-8 at a relatively low concentration of 0.1 nM, a
significant increase in bead binding was detected over the time course
of stimulation (Fig. 2). A much stronger response was elicited through
cross-linking of L-selectin with a secondary antibody. The combination
of co-stimulation through L-selectin and IL-8 tended to increase the
extent of bead binding over activation through L-selectin alone.

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Fig. 2.
Neutrophil adhesion to albumin-coated latex
beads in response to stimulation through cross-linking of L-selectin
and IL-8. Neutrophil adhesion was stimulated by addition of 0.1 nM IL-8 and/or L-selectin cross-linking (20 µg/ml
HuDREG200 cross-linked with 10 µg/ml goat anti-human IgG). Data
represent the number of beads bound to cells at each time point before
and after stimulation relative to the number bound to untreated
(typically 0.5-1 bead/PMN). Plotted are the kinetics of adhesion from
one experiment representative of five separate donors.
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Previous work had implicated MAP kinases in signaling through adhesion
molecules and in chemotactic stimulation of superoxide production (45,
46). In particular, p38 MAPK has been recently shown to be involved in
signaling through 2-integrins (45). We therefore
examined whether the sensitization induced by cross-linking L-selectin
by addition of both HuDREG200 and HuDREG55 involved activation of p38
MAPK in the signaling pathway. We tested this using a high affinity
inhibitor of p38 MAPK synthesized by Merck Research Laboratories,
designated Merck C (47). Merck C is a potent and specific blocker of
p38 MAPK, with an IC50 of 0.24 nM for isolated
enzyme and an IC50 of ~2.2 nM for inhibition
of p38-induced cellular function. Merck A is a non-functional isomer that has a similar chemical composition (47). To determine the effective concentration for inhibition of neutrophil activation, we
analyzed cell shape change stimulated by cross-linking of L-selectin. As shown in Fig. 3, Merck C was a potent
inhibitor of shape change at all concentrations tested. In contrast,
Merck A elicited modest inhibition of shape change only at a
concentration of 100 nM. Based upon these results, Merck C
was used at concentrations of 3 nM or greater for
inhibition of L-selectin induced activation. Merck A, which
exhibited no inhibitory activity in this dose range, served as a
nonspecific control for Merck C. Incubation of neutrophils with the
Merck compounds at concentrations up to 50 nM for 1 h at 37 °C did not result in any increase in cell lysis or death (not
shown; see "Experimental Procedures").

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Fig. 3.
Neutrophil shape change in response to
cross-linking of L-selectin and inhibition of p38 MAPK.
Neutrophils (106/ml) were preincubated with Merck compounds
at the indicated concentrations for 45 min at 37 °C. Cell samples
were stimulated by cross-linking L-selectin as described under
"Experimental Procedures" and then fixed and the morphology was
assessed using a phase-contrast microscope. Cells were scored based on
their shape change response to cross-linking L-selectin. Maximum
response was defined as the fraction of cells with extensive ruffling
of the plasma membrane and pseudopod formation. Data shown are the
fraction of cells responding to L-selectin stimulation in the presence
of Merck compounds. The data were compiled from two experiments for
Merck A and from four experiments for Merck C.
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We next assessed whether cross-linking L-selectin by the binding of the
two humanized DREG mAbs would elicit phosphorylation of p38 MAPK that
could be inhibited by Merck C. Using commercial antibodies specific for
the dually phosphorylated state of p38 MAPK, we found that
cross-linking of L-selectin enhanced phosphorylation within 1 min.
Compared with the untreated control, an increase in the phosphorylation
of p38 MAPK of as much as 7-fold was detected (Fig.
4a). The pattern of p38 MAPK
phosphorylation showed a decrease at 2 min and a second peak at 3-5
min. These kinetics varied only slightly between experiments, as shown
in the densitometry results from four separate experiments (Fig.
4b). As can be seen, the peak of phosphorylation at 1 min
and the succeeding drop at 2 min were statistically significant. It
should be noted that a minor proteolytic product of p38 was
occasionally evident (see 1 min point in Fig. 4a).

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Fig. 4.
a, ligation of L-selectin and the
kinetics of phosphorylation of the MAP kinases. Neutrophils (5 × 106/ml) were preincubated with Merck A or Merck C (10 nM) for 45 min at 37 °C and stimulated in the presence
of HuDreg200 and HuDREG55 added together at 10 µg/ml for between 1 and 10 min. Reactions were stopped by centrifugation and cell pellets
were rapidly frozen in liquid nitrogen and suspended in ice-cold lysis
buffer. The supernatants were resolved using 12% discontinuous
SDS-polyacrylamide gels, proteins were transferred to nitrocellulose
membranes, and the dually phosphorylated forms of: A, p38
MAPK on Thr180/Tyr182, and
B, p44/42 MAP kinase (ERK1/2) on
Thr202/Tyr204 were detected by Western blot
analysis. Shown are the kinetics from unstimulated cells and those
incubated for the indicated time with anti-L-selectins. Merck A- and
C-treated samples correspond to 5-min incubations with
anti-L-selectins. b, densitometric analysis of the kinetics
of phosphorylation of p38 MAPK. Four experiments were conducted in
which the dually phosphorylated form of p38 MAPK was detected as in
a. Equal loading of the lanes was verified using Western
blots to p38 MAPK protein or ERK1/2 protein. The intensities of the
bands for doubly phosphorylated p38 MAPK were measured with Adobe
Photoshop and corrected for background intensities. The intensities in
each experiment were normalized using the maximum point in each
experiment (generally the 1 min point). The data are expressed as the
mean (± S.E., n = 4) of these relative intensities.
The p values were determined by one-way ANOVA with
significance between indicated groups analyzed by a Newman-Keuls
post-test. c, densitometric analysis of the kinetics of
phosphorylation of ERK1/2. Two experiments were conducted in which
double phosphorylation of ERK1/2 was detected as described in
a. The intensities were measured and analyzed as detailed in
the legend to a. The data are expressed as the mean (± S.E., n = 2) of the relative intensities. d,
MAPK activity and Merck dependent inhibition. Activation of MAPK kinase
in response to cross-linking of L-selectin was assayed as described
under "Experimental Procedures" by measuring the incorporation of
radiolabeled phosphate [ -33P]ATP into heat shock
protein-27 (hsp-27), the downstream substrate of p38 MAPK. Neutrophils
were preincubated for 45 min at 37 °C in the absence or presence of
Merck A or Merck C (5 nM). Phosphorylation of hsp-27 was
resolved by SDS-PAGE and the gel was subjected to PhosphorImager
quantitation. The intensities were normalized as fractions of unstimulated control samples. Data are shown as kinase
activity corresponding to cross-linked L-selectin (X-Link)
in the presence of Merck compounds relative to controls from five
separate experiments (mean ± S.E., * represents p < 0.05 compared with X-Link alone).
|
|
Phosphorylation of ERK1/2 (p44/42 MAP kinase) also increased during
this time period, but was delayed in onset (Fig. 4a). The
lower of the bands, ERK2, was the most prominent following ligation
with L-selectin. Fig. 4c shows the combined densitometry results from two experiments, indicating that peak phosphorylation of
ERK1/2 occurred at 5-10 min. Merck C almost completely inhibited the
phosphorylation of p38 MAPK, but not ERK1/2. We confirmed that Merck C,
at concentrations up to 30 nM, had no effect upon the
phosphorylation of ERK1/2, using a potent stimulus for these phosphoproteins (5 ng/ml granulocyte-macrophage colony stimulating factor; data not shown). The control compound, Merck A had no effect on
either phosphoprotein.
As shown in Fig. 4d, we also confirmed that the
tyrosine-phosphorylated p38 MAPK that was induced by cross-linking
L-selectin was effective at phosphorylating its downstream substrate
MAPK-activated protein (heat shock protein hsp27). Preincubation with
Merck A did not alter the kinase activity, whereas Merck C blocked p38 MAPK activity to baseline values.
We next determined whether stimulation of degranulation was dependent
upon p38 MAPK and inhibitable by Merck C. As shown in Fig.
5, Merck C did not significantly inhibit
the release of azurophil granules (MPO and -glucuronidase). However,
up-regulation of Mac-1, the tertiary and secretory granule marker,
showed statistically significant inhibition with Merck C. This
inhibition occurred with stimulation through L-selectin alone, and thus
paralleled the observed activation of Mac-1 adhesive function.
Inhibition of the release of lactoferrin, the secondary granule marker,
was significant for both cross-linking alone and co-stimulation with IL-8. Thus, secretion from the more labile granule pools was blocked by
Merck C. As expected, Merck A exerted no significant inhibitory effect
on degranulation. It should also be noted that none of the above
treatments resulted in loss of neutrophil viability (see
"Experimental Procedures").

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Fig. 5.
Degranulation of neutrophils in the presence
of Merck C inhibitor of p38 MAPK. Neutrophils were preincubated in
buffer alone (control), or with the high affinity Merck C inhibitor of
p38 MAPK, or the inactive compound Merck A at 3 nM for 45 min at 37 °C. Degranulation was induced by addition of 1 nM IL-8 and/or L-selectin cross-linking (10 µg/ml
HuDreg55 and HuDreg200). Plotted is the surface expression of Mac-1 as
mean fluorescence intensity ± S.E. Also shown is the % release
of total content of lactoferrin, myeloperoxidase, and -glucuronidase
compared with lysed neutrophils, plotted as mean ± S.E. from five
separate experiments. The p values were determined by
repeated measures ANOVA with significance between indicated groups
analyzed by a Newman-Keuls post-test.
|
|
There was also a marked inhibitory effect of the p38 MAPK antagonist on
Mac-1-dependent adhesion in response to stimulation through
L-selectin and IL-8 (Fig. 6). When
compared with the maximum adhesion via Mac-1 elicited by cross-linking
L-selectin, pretreating neutrophils with Merck C (3 nM)
inhibited the response by ~50%. This was significantly greater than
that observed with Merck A, which was identical to stimulation through
L-selectin alone. Inhibition of p38 MAPK also significantly decreased
Mac-1-dependent adhesion stimulated through IL-8 alone.
However, the level of inhibition on co-stimulation through IL-8 and
cross-linking was no more than that for cross-linking alone.

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Fig. 6.
Neutrophil adhesion to albumin-coated latex
microspheres in the presence of Merck C inhibitor of p38 MAPK.
Neutrophils were preincubated in buffer alone (control), or with the
high affinity Merck C inhibitor of p38 MAPK, or the inactive compound
Merck A at 3 nM for 45 min at 37 °C. Bead binding was
quantitated at peak adhesion (~6 min as shown in the kinetics of Fig.
2) for L-selectin cross-linking (X-Link) and IL-8 alone or in
combination as denoted. Data represent the fractional decrease from the
level of bead binding in the presence of stimuli and absence of Merck
compounds. Plotted are the mean ± S.E. inhibition (% maximum
response) computed from each of five separate experiments. The
p values were determined by one-way ANOVA with significance
between the indicated groups analyzed by a Newman-Keuls
post-test.
|
|
 |
DISCUSSION |
In addition to their roles in mediating the capture and adhesion
of neutrophils to the endothelium, integrins and selectins appear to be
involved in both outside-in and inside-out signaling (22, 27, 32,
48-52). For example, the 2-integrins CD11b and CD11c
can serve as cis-acting receptors that transduce signals upon interaction with glycosylphosphatidylinositol-linked receptors (49), particularly Fc RIII (51, 52) and CD14. In previous studies, we
examined the process by which L-selectin served to activate adhesive
functions via 2-integrins (31-33). We have also reported that co-stimulation through L-selectin and chemotactic factors
results in a host of biophysical alterations associated with
enhancement of the microvascular sequestration of neutrophils at
sites of inflammation (53).
It was of interest to see if the signaling originating through
L-selectin would influence cellular responses that typically occur
following margination and rolling in the inflamed vasculature. In this
regard, a unique finding here was that cross-linking L-selectin by
simultaneous application of HuDREG200 and HuDREG55 sensitized neutrophils to degranulate in response to a chemotactic stimulus (IL-8). These data extend those from a recent report showing that cross-linking of L-selectin can induce some degranulation on its own
(54). These authors showed that ligation of either Mac-1 or L-selectin
induced the secretion of MMP-9, a marker of tertiary granules, but not
-glucuronidase. As shown in Fig. 1, IL-8 dose dependently
increased the expression of Mac-1 from secondary, tertiary, and
secretory granules (10-13). We could up-regulate Mac-1 in response to
as little as 0.1 nM IL-8. This appeared to reflect the
mobilization of the labile tertiary and secretory granules since
neither lactoferrin (secondary granules) nor MPO and -glucuronidase
(primary granules) were significantly released in response to the low
dose of IL-8. Cross-linking L-selectin proved to be as potent a
sensitizing agent as cytochalasin B for eliciting secretion of
secondary, tertiary, and secretory granules in response to low doses of
IL-8 (Fig. 1, A and B). For primary granule
release (Fig. 1, C and D), the response to
ligation of L-selectin was insignificant, except in combination with
cytochalasin B, with which it was synergistic. Taken together, the data
show that ligation of L-selectin is a potent sensitizing stimulus to amplify degranulation in response to low doses of IL-8 and sufficient to signal release of Mac-1 and lactoferrin.
Early studies on the regulation of L-selectin suggested it as a target
of intracellular signaling. In particular, cellular activation led to
enhanced adhesive function (48, 55, 56) of L-selectin and subsequently
to its shedding from the cell surface (22, 57). More recently, it has
been appreciated that L-selectin can also signal function in
neutrophils. For 2-integrins,
adhesion-dependent signaling has been shown to involve
src kinases (58), p21ras (59), syk (60),
hck/fgr/lyn (58, 61), and tyrosine
phosphorylation (62, 63). This signaling is proximal to activation of
the multiple MAP kinases (28, 29, 64, 65) that have drawn considerable
interest as pharmacologic targets. Like the integrins, cross-linking of
L-selectin can sensitize the cells to respond to other stimuli,
resulting in potentiation of the oxidative burst (24, 66) and enhanced
adhesion through both Mac-1 and LFA-1 (27, 31-33, 67). Similarly,
ligation of L-selectin can produce several neutrophil responses on
their own, in the absence of additional stimuli, including increases in
Mac-1 avidity, degranulation, and actin polymerization (25, 31, 46).
MAP kinases have been implicated in adhesion-related signaling (68),
particularly through L-selectins (28). In fact, L-selectin activates
JNK in T lymphocytes (69).
The three branches of the MAPK signaling pathway (ERK1/2, JNK, and p38)
have all been shown to be present in neutrophils (64, 70) and are
activated in response to potent chemotaxins such as fMLP (71). It is
believed that the relative activities of these three specific kinases
are in part responsible for the multiplicity in responses effected by a
single agonist (72). For example, tumor necrosis factor- ,
granulocyte colony stimulating factor, and granulocyte-macrophage
colony stimulating factor caused the phosphorylation of p38 MAPK, ERK1,
and ERK2 with dose-response and kinetic parameters that were
stimulus-dependent (73). In this report, the production of
superoxide correlated with phosphorylation of p38 MAPK.
We focused on p38 MAPK as the primary intracellular signaling pathway
for several reasons. First, while priming can activate all three
branches of the MAPK pathway (72) in neutrophils, the p38 branch is
particularly important in sensitizing neutrophils to chemotactic
stimuli (45, 74, 75). Second, p38 MAPK appears to be involved in
signaling through adhesion molecules such as the
2-integrins (45, 76), and is sufficient for some
functions such as chemotaxis in response to transforming growth
factor- 1 (77). Third, it appears to be central in neutrophil
responses to important physiologic stimuli such as fMLP and tumor
necrosis factor (65, 76, 78-80). Fourth, the p38 pathway may be
particularly important since it can lead to the phosphorylation and
activation of phospholipase A2 (81, 82). Arachidonic acid,
the product of phospholipase A2, may in turn activate p38
(83). Previous work has suggested that the p38 MAPK pathway may be
involved in augmenting degranulation (80), but had not demonstrated
activation of degranulation per se (77). This property makes
it ideal for studying the priming process without directly stimulating
the cells. Finally, p38 appears to be required for the production of
IL-8 by neutrophils (78), but IL-8 does not necessarily signal through
p38 (84). This means that the stimulus for our experiments (IL-8) does
not necessarily use the same pathway as our sensitizing agent
(L-selectin), allowing the possibility of dissecting the pathway of
L-selectin-mediated signaling.
Our work is the first to demonstrate that stimulation through
cross-linking L-selectin serves to activate p38 MAPK. Waddell et
al. (28) showed that this stimulus induced the phosphorylation of
proteins in the 40-kDa range. One of these proteins co-migrated with
EKR1/2, providing a tentative identification. Our findings indicate
that a different co-migrating protein, namely p38 MAPK, is the initial
response to cross-linking. The kinetics of phosphorylation of p38 MAPK
were rapid peaking, within 1 min, followed by a decrease at 2 min, and
a subsequent second peak at 3-5 min. These kinetics are distinctly
different from those of phosphorylation of ERK1/2, which took place
after a delay of 3-5 min. The dephosphorylation of p38 MAPK observed
at 2 min may reflect the activity of a phosphatase, as previously
suggested in cells stimulated by cross-linking of L-selectin (28).
Nonetheless, the phosphorylated p38 MAPK retained activity as indicated
by the ability of neutrophil cell lysates to phosphorylate the
endogenous downstream substrate hsp27 (Fig. 4d). Our data
showing that the phosphorylation of p38 MAPK can be modulated within
seconds to minutes implies a mechanism in which L-selectin acting as a
signaling molecule may regulate rapid responses of neutrophils
including degranulation, adhesion, shape change, and superoxide
generation. Our data also showed that inhibition of phosphorylation was
specific for p38 MAPK (Fig. 4a, A);
phosphorylation of ERK was unaffected (Fig. 4a,
B, and other experiments using granulocyte-macrophage colony
stimulating factor as a stimulus). This conclusion is supported by far
more detailed studies from the Merck Research Laboratories (47). We
found that the effectiveness of Merck C in inhibition of shape change
induced by L-selectin was comparable to that reported by Merck Research
for lipopolysaccharide-stimulated release of tumor necrosis factor-
from human blood (~2.2 nM) (47). At nanomolar
concentrations, Merck C markedly inhibited the kinase activity of p38
and activation of Mac-1 dependent adhesion stimulated by cross-linking
of L-selectin (Figs. 4 and 6). We also found that signaling through
L-selectin was more sensitive to inhibition of p38 MAPK than signaling
through IL-8. The relative insensitivity of IL-8 signaling to
inhibition of p38 is consistent with previous work (69, 84). In a
recent publication (85), we provide evidence of neutrophil activation
following rolling on E-selectin. The transition from rolling to firm
adhesion was in part dependent on tethering through L-selectin and
signaling of 2-integrin dependent adhesion to ICAM-1.
Consistent with the current results was the finding of compete
inhibition of neutrophil firm adhesion when blocking p38 MAPK with
Merck C at 5 nM. By comparison, treating neutrophils with
an inhibitor of p42/44 ERK1/2 kinase, PD98059 at 10 µM,
inhibited firm adhesion only slightly (85). Taken together, the data
suggest that signaling between L-selectin and
2-integrins occurs primarily through p38 MAPK.
We also showed that clustering of L-selectin primed for secretion of
secondary, tertiary, and secretory granules and that blocking
phosphorylation of p38 MAPK inhibited this process. In contrast, Merck
C did not significantly block the release of azurophil granules. We
speculate that signaling between L-selectin and azurophil granule
secretion could involve the ERK pathway. Alternatively, the signaling
pathways leading to azurophil degranulation may be upstream of the MAP
kinases. An additional factor is that azurophil degranulation requires
relatively high concentrations of agonist, and is highly dependent on
Ca2+ signaling pathways. Our findings are in accord with
the report that inhibition of the MAPK pathway does not block
superoxide generation and azurophil granule release (86).
An additional finding was that stimulation by IL-8 of Mac-1 function
was inhibited by Merck C (Fig. 6). In contrast, degranulation induced
by IL-8 was not blocked by Merck C (Fig. 5). Hence, the signal
transduction pathways from IL-8 appear to diverge before producing
these two responses. Furthermore, for both Mac-1 function and
degranulation, sensitivity to Merck C was the same for IL-8 alone as it
was for the combination of IL-8 and L-selectin cross-linking. These
data thus suggest that the signal from IL-8 functionally dominates that
of cross-linking L-selectin.
In summary, we report that ligation of L-selectin activates p38 MAPK
and makes neutrophils more susceptible to degranulation by the stimulus
IL-8. This priming is potent, rapid (on the order of 1 min), and could
have significant pathophysiologic consequences. Signaling through
L-selectin leading to shape change, enhanced CD11b/CD18 function, and
release of secondary, tertiary, and secretory granules is triggered
directly through p38 MAPK and can be strongly blocked by Merck C, a
highly specific inhibitor of p38 MAPK. The implication is that
clustering of L-selectin as neutrophils migrate at vascular sites of
inflammation may serve to enhance the signaling through chemotactic
agents of subsequent adhesive and secretory functions.
 |
FOOTNOTES |
*
This work was supported by National Institutes of Health
Grants R01 DK 32471 (to J. E. S.), R01 HL42550 (C. Wayne
Smith, Director, Leukocyte Biology Section), and R01 AI 31652 (to
S. I. S.), the Whitaker Foundation (to S. I. S.),
and American Heart Association Established Investigator Award 9640162N
(to S. I. S.).The costs of publication of this
article were defrayed in part by the
payment of page charges. The article
must therefore be hereby marked
"advertisement" in
accordance with 18 U.S.C. Section
1734 solely to indicate this fact.
§
To whom correspondence should be addressed: Children's Nutrition
Research Center, 1100 Bates, Rm. 6014, Baylor College of Medicine,
Houston, TX 77030-2600. Tel: 713-770-3690; Fax: 713-770-4366; E-mail: jsmolen@bcm.tmc.edu.
Published, JBC Papers in Press, March 16, 2000, DOI 10.1074/jbc.M906232199
 |
ABBREVIATIONS |
The abbreviations used are:
ICAM-1, intracellular adhesion molecule 1;
IL, interleukin;
MAPK, mitogen-activated protein kinase;
HSA, human serum albumin;
PAGE, polyacrylamide gel electrophoresis;
MPO, myeloperoxidase;
ERK, extracellular signal-regulated kinase.
 |
REFERENCES |
| 1.
|
Henricks, P. A. J.,
Van der Tol, M. E.,
and Verhoef, J.
(1984)
Immunology
52,
671-678
|
| 2.
|
Smith, C. W.,
Kishimoto, T. K.,
Abbass, O.,
Hughes, B.,
Rothlein, R.,
McIntire, L. V.,
Butcher, E.,
and Anderson, D. C.
(1991)
J. Clin. Invest.
87,
609-618
|
| 3.
|
Lawrence, M. B.,
and Springer, T. A.
(1991)
Cell
65,
859-873
|
| 4.
|
Smith, C. W.,
Marlin, S. D.,
Rothlein, R.,
Toman, C.,
and Anderson, D. C.
(1989)
J. Clin. Invest.
83,
2008-2017
|
| 5.
|
Kishimoto, T. K.,
Jutila, M. A.,
Berg, E. L.,
and Butcher, E. C.
(1989)
Science
245,
1238-1241
|
| 6.
|
Zimmerman, G. A.,
Prescott, S. M.,
and McIntyre, T. M.
(1992)
Immunol. Today
13,
93-100
|
| 7.
|
Hammer, D. A.,
and Apte, S. M.
(1992)
Biophys. J.
63,
35-57
|
| 8.
|
Crockett-Torabi, E.
(1998)
J. Leukocyte Biol.
63,
1-14
|
| 9.
|
Simon, S. I.,
Chambers, J. D.,
Butcher, E.,
and Sklar, L. A.
(1992)
J. Immunol.
149,
2765-2771
|
| 10.
|
Todd, R. F., III,
Arnaout, M. A.,
Rosin, R. E.,
Crowley, C. A.,
Peters, W. A.,
and Babior, B. M.
(1984)
J. Clin. Invest.
74,
1280-1290
|
| 11.
|
Petrequin, P. R.,
Todd, R. F., III,
Devall, L. J.,
Boxer, L. A.,
and Curnutte, J. T., III
(1987)
Blood
69,
605-610
|
| 12.
|
Stevenson, K. B.,
Nauseef, W. M.,
and Clark, R. A.
(1987)
J. Immunol.
139,
3759-3763
|
| 13.
|
Sengelov, H.,
Kjeldsen, L.,
Diamond, M. S.,
Springer, T. A.,
and Borregaard, N.
(1993)
J. Clin. Invest.
92,
1467-1476
|
| 14.
|
Bainton, D. F.
(1973)
J. Cell Biol.
58,
249-264
|
| 15.
|
Bentwood, B. J.,
and Henson, P. M.
(1980)
J. Immunol.
124,
855-862
|
| 16.
|
Niessen, H. W. M.,
and Verhoeven, A. J.
(1992)
Cell. Signal.
4,
501-509
|
| 17.
|
Zaman, W.,
Mitsuyama, T.,
Hatakenaka, M.,
Kang, D.,
Minakami, S.,
and Takeshige, K.
(1994)
J. Biochem. (Tokyo)
115,
238-244
|
| 18.
|
Smolen, J. E.,
and Weissmann, G.
(1981)
Biochim. Biophys. Acta
672,
197-206
|
| 19.
|
Hanlon, W. A.,
Stolk, J.,
Davies, P.,
Humes, J. L.,
Mumford, R.,
and Bonney, R. J.
(1991)
J. Leukocyte Biol.
50,
43-48
|
| 20.
|
Estensen, R. D.,
White, J. G.,
and Holmes, B.
(1974)
Nature
248,
347-348
|
| 21.
|
Niessen, H. W.,
Kuijpers, T. W.,
Roos, D.,
and Verhoeven, A. J.
(1991)
Cell. Signal.
3,
625-633
|
| 22.
|
Walzog, B.,
Seifert, R.,
Zakrzewicz, A.,
Gaehtgens, P.,
and Ley, K.
(1994)
J. Leukocyte Biol.
56,
625-635
|
| 23.
|
Dapino, P.,
Dallegri, F.,
Ottonello, L.,
and Sacchetti, C.
(1993)
Clin. Exp. Immunol.
94,
533-538
|
| 24.
|
Waddell, T. K.,
Fialkow, L.,
Chan, C. K.,
Kishimoto, T. K.,
and Downey, G. P.
(1994)
J. Biol. Chem.
269,
18485-18491
|
| 25.
|
Wize, J.,
Sopata, I.,
Smerdel, A.,
and Maslinski, S.
(1998)
Inflamm. Res.
47,
325-327
|
| 26.
|
Crockett-Torabi, E.,
and Fantone, J. C.
(1997)
Am. J. Physiol.
272,
H1302-H1308
|
| 27.
|
Crockett-Torabi, E.,
Sulenbarger, B.,
Smith, C. W.,
and Fantone, J. C.
(1995)
J. Immunol.
154,
2291-2302
|
| 28.
|
Waddell, T. K.,
Fialkow, L.,
Chan, C. K.,
Kishimoto, T. K.,
and Downey, G. P.
(1995)
J. Biol. Chem.
270,
15403-15411
|
| 29.
|
Hidari, K. I.-P. J.,
Weyrich, A. S.,
Zimmerman, G. A.,
and McEver, R. P.
(1997)
J. Biol. Chem.
272,
28750-28756
|
| 30.
|
Steeber, D. A.,
Engel, P.,
Miller, A. S.,
Sheetz, M. P.,
and Tedder, T. F.
(1997)
J. Immunol.
159,
952-963
|
| 31.
|
Tsang, Y. T. M.,
Neelamegham, S.,
Burns, A. R.,
Berg, E. L.,
Smith, C. W.,
and Simon, S. I.
(1997)
J. Immunol.
159,
4566-4577
|
| 32.
|
Simon, S. I.,
Burns, A. R.,
Taylor, A. D.,
Gopalan, P. K.,
Lynam, E. B.,
Sklar, L. A.,
and Smith, C. W.
(1995)
J. Immunol.
155,
1502-1514
|
| 33.
|
Gopalan, P. K.,
Smith, C. W.,
Lu, H. F.,
Berg, E. L.,
McIntire, L. V.,
and Simon, S. I.
(1997)
J. Immunol.
158,
367-375
|
| 34.
|
Hellman, B.,
Gylfe, E.,
Wesslen, N.,
Hallberg, A.,
Grapengiesser, E.,
and Marcstrom, A.
(1989)
Exp. Clin. Endocrinol.
93,
125-135
|
| 35.
|
Hughes, B. J.,
Hollers, J. C.,
Crockett-Torabi, E.,
and Smith, C. W.
(1992)
J. Clin. Invest.
90,
1687-1696
|
| 36.
|
Simon, S. I.,
Chambers, J. D.,
and Sklar, L. A.
(1990)
J. Cell Biol.
111,
2747-2756
|
| 37.
|
Laemmli, U. F.
(1970)
Nature
227,
680-685
|
| 38.
|
Towbin, H.,
Staehelin, T.,
and Gordon, J.
(1979)
Proc. Natl. Acad. Sci. U. S. A.
76,
4350-4354
|
| 39.
|
Smolen, J. E.,
and Sandborg, R. R.
(1990)
Biochim. Biophys. Acta
1052,
133-142
|
| 40.
|
Brittinger, G. R.,
Hirschhorn, R.,
Douglas, S. D.,
and Weissmann, G.
(1968)
J. Cell Biol.
37,
394-411
|
| 41.
|
Bretz, U.,
and Baggiolini, M.
(1974)
J. Cell Biol.
63,
251-269
|
| 42.
|
Hetherington, S. V.,
Spitznagel, J. K.,
and Quie, P. G.
(1983)
J. Immunol. Methods
65,
183-190
|
| 43.
|
Bezwoda, W. R.,
Baynes, R. D.,
Khan, Q.,
and Mansoor, N.
(1985)
Clin. Chim. Acta
151,
61-69
|
| 44.
|
Wacker, W. E. C.,
Ulmer, D. D.,
and Vallee, B. L.
(1956)
N. Engl. J. Med.
255,
449-456
|
| 45.
|
Detmers, P. A.,
Zhou, D. H.,
Polizzi, E.,
Thieringer, R.,
Hanlon, W. A.,
Vaidya, S.,
and Bansal, V.
(1998)
J. Immunol.
161,
1921-1929
|
| 46.
|
Ng-Sikorski, J.,
Lindén, L.,
Eierman, D.,
Franzen, L.,
Molony, L.,
and Andersson, T.
(1996)
J. Cell Sci.
109,
2361-2369
|
| 47.
|
Liverton, N. J.,
Butcher, J. W.,
Claiborne, C. F.,
Claremon, D. A.,
Libby, B. E.,
Nguyen, K. T.,
Pitzenberger, S. M.,
Selnick, H. G.,
Smith, G. R.,
Tebben, R.,
Vacca, J. P.,
Varga, S. L.,
Agarwal, L.,
Dancheck, K.,
Forsyth, A. J.,
Fletcher, D. S.,
Frantz, B.,
Hanlon, W. A.,
Harper, C. P.,
Hofsess, S. J.,
Kotsura, M.,
Lin, J.,
Luell, S.,
O'Neill, E. A.,
Orevillo, C. J.,
Pang, M.,
Parsons, J.,
Rolando, A.,
Sahly, Y.,
Visco, D. M.,
and O'Keefe, S. J.
(1999)
J. Med. Chem.
42,
2180-2190
|
| 48.
|
Rainger, G. E.,
Buckley, C.,
Simmons, D. L.,
and Nash, G. B.
(1997)
Curr. Biol.
7,
316-325
|
| 49.
|
Todd, R. F., III,
and Petty, H. R.
(1997)
J. Lab. Clin. Med.
129,
492-498
|
| 50.
|
Liles, W. C.,
Ledbetter, J. A.,
Waltersdorph, A. W.,
and Klebanoff, S. J.
(1995)
J. Leukocyte Biol.
58,
690-697
|
| 51.
|
Gadd, S. J.,
Eher, R.,
Majdic, O.,
and Knapp, W.
(1994)
Immunology
81,
611-617
|
| 52.
|
Zhou, M.,
and Brown, E. J.
(1994)
J. Cell Biol.
125,
1407-1416
|
| 53.
|
Simon, S. I.,
Cherapanov, V.,
Nadra, I.,
Waddell, T. K.,
Seo, S. M.,
Wang, Q.,
Doerschuk, C. M.,
and Downey, G. P.
(1999)
J. Immunol.
163,
2891-2901
|
| 54.
|
Yan, S. R.,
and Berton, G.
(1998)
J. Leukocyte Biol.
64,
401-408
|
| 55.
|
Buttrum, S. M.,
Hatton, R.,
and Nash, G. B.
(1993)
Blood
82,
1165-1174
|
| 56.
|
Spertini, O.,
Kansas, G. S.,
Munro, J. M.,
Griffin, J. D.,
and Tedder, T. F.
(1991)
Nature
349,
691-694
|
| 57.
|
Walcheck, B.,
Kahn, J.,
Fisher, J. M.,
Wang, B. B.,
Fisk, R. S.,
Payan, D. G.,
Feehan, C.,
Betageri, R.,
Darlak, K.,
Spatola, A. F.,
and Kishimoto, T. K.
(1996)
Nature
380,
720-723
|
| 58.
|
Lowell, C. A.,
Fumagalli, L.,
and Berton, G.
(1996)
J. Cell Biol.
133,
895-910
|
| 59.
|
Zheng, L. M.,
Sjölander, A.,
Eckerdal, J.,
and Andersson, T.
(1996)
Proc. Natl. Acad. Sci. U. S. A.
93,
8431-8436
|
| 60.
|
Fernandez, R.,
and Suchard, S. J.
(1998)
J. Immunol.
160,
5154-5162
|
| 61.
|
Berton, G.,
Fumagalli, L.,
Laudanna, C.,
and Sorio, C.
(1994)
J. Cell Biol.
126,
1111-1121
|
| 62.
|
Grinstein, S.,
Furuya, W.,
and Downey, G. P.
(1992)
J. Biol. Chem.
267,
18122-18125
|
| 63.
|
Fuortes, M.,
Jin, W.,
and Nathan, C.
(1994)
J. Cell Biol.
127,
1477-1483
|
| 64.
|
Thompson, H. L.,
Marshall, C. J.,
and Saklatvala, J.
(1994)
J. Biol. Chem.
269,
9486-9492
|
| 65.
|
Krump, E.,
Sanghera, J. S.,
Pelech, S. L.,
Furuya, W.,
and Grinstein, S.
(1997)
J. Biol. Chem.
272,
937-944
|
| 66.
|
Fröhlich, D.,
Spertini, O.,
and Moser, R.
(1998)
Blood
91,
2558-2564
|
| 67.
|
Hwang, S. T.,
Singer, M. S.,
Giblin, A.,
Yednock, T. A.,
Bacon, K. B.,
Simon, S. I.,
and Rosen, S. D.
(1996)
J. Exp. Med.
184,
1343-1348
|
| 68.
|
Pillinger, M. H.,
Feoktistov, A. S.,
Capodici, C.,
Solitar, B.,
Levy, J.,
Oei, T. T.,
and Philips, M. R.
(1996)
J. Biol. Chem.
271,
12049-12056
|
| 69.
|
Brenner, B.,
Weinmann, S.,
Grassmé, H.,
Lang, F.,
Linderkamp, O.,
and Gulbins, E.
(1997)
Immunology
92,
214-219
|
| 70.
|
Waterman, W. H.,
and Sha'afi, R. I.
(1995)
Biochem. J.
307,
39-45
|
| 71.
|
Rane, M. J.,
Carrithers, S. L.,
Arthur, J. M.,
Klein, J. B.,
and McLeish, K. R.
(1997)
J. Immunol.
159,
5070-5078
|
| 72.
|
Coffer, P. J.,
and Koenderman, L.
(1997)
Immunol. Lett.
57,
27-31
|
| 73.
|
Suzuki, K.,
Hino, M.,
Hato, F.,
Tatsumi, N.,
and Kitagawa, S.
(1999)
Blood
93,
341-349
|
| 74.
|
Nick, J. A.,
Avdi, N. J.,
Gerwins, P.,
Johnson, G. L.,
and Worthen, G. S.
(1996)
J. Immunol.
156,
4867-4875
|
| 75.
|
McLeish, K. R.,
Knall, C.,
Ward, R. A.,
Gerwins, P.,
Coxon, P. Y.,
Klein, J. B.,
and Johnson, G. L.
(1998)
J. Leukocyte Biol.
64,
537-545
|
| 76.
|
Schnyder, B.,
Meunier, P. C.,
and Car, B. D.
(1998)
Biochem. J.
331,
489-495
|
| 77.
|
Hannigan, M.,
Zhan, L. J.,
Ai, Y. X.,
and Huang, C. K.
(1998)
Biochem. Biophys. Res. Commun.
246,
55-58
|
| 78.
|
Zu, Y. L.,
Qi, J. F.,
Gilchrist, A.,
Fernandez, G. A.,
Vazquez-Abad, D.,
Kreutzer, D. L.,
Huang, C. K.,
and Sha'afi, R. I.
(1998)
J. Immunol.
160,
1982-1989
|
| 79.
|
el Benna, J.,
Han, J. H.,
Park, J. W.,
Schmid, E.,
Ulevitch, R. J.,
and Babior, B. M.
(1996)
Arch. Biochem. Biophys.
334,
395-400
|
| 80.
|
Nahas, N.,
Molski, T. F. P.,
Fernandez, G. A.,
and Sha'afi, R. I.
(1996)
Biochem. J.
318,
247-253
|
| 81.
|
Nahas, N.,
Waterman, W. H.,
and Sha'afi, R. I.
(1996)
Biochem. J.
313,
503-508
|
| 82.
|
Waterman, W. H.,
Molski, T. F. P.,
Huang, C. K.,
Adams, J. L.,
and Sha'afi, R. I.
(1996)
Biochem. J.
319,
17-20
|
| 83.
|
Hii, C. S. T.,
Huang, Z. H.,
Bilney, A.,
Costabile, M.,
Murray, A. W.,
Rathjen, D. A.,
Der, C. J.,
and Ferrante, A.
(1998)
J. Biol. Chem.
273,
19277-19282
|
| 84.
|
Knall, C.,
Worthen, G. S.,
and Johnson, G. L.
(1997)
Proc. Natl. Acad. Sci. U. S. A.
94,
3052-3057
|
| 85.
|
Simon, S. I.,
Hu, Y.,
Vestweber, D.,
and Smith, C. W.
(2000)
J. Immunol.
164,
4348-4358
|
| 86.
|
Mócsai, A.,
Bánfi, B.,
Kapus, A.,
Farkas, G.,
Geiszt, M.,
Buday, L.,
Faragó, A.,
and Ligeti, E.
(1997)
Biochem. Pharmacol.
54,
781-789
|
Copyright © 2000 by The American Society for Biochemistry and Molecular Biology, Inc.

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|
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|
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|
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[Abstract]
[Full Text]
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|
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|
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[Abstract]
[Full Text]
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|
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|
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[Abstract]
[Full Text]
[PDF]
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|
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|
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|
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|
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166(10):
6294 - 6300.
[Abstract]
[Full Text]
[PDF]
|
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|

|
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|
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J. Immunol.,
December 15, 2000;
165(12):
7164 - 7170.
[Abstract]
[Full Text]
[PDF]
|
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|

|
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|
 |
 
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J. Biol. Chem.,
November 17, 2000;
275(47):
36713 - 36719.
[Abstract]
[Full Text]
[PDF]
|
 |
|

|
 |

|
 |
 
J. Laferriere, F. Houle, M. M. Taher, K. Valerie, and J. Huot
Transendothelial Migration of Colon Carcinoma Cells Requires Expression of E-selectin by Endothelial Cells and Activation of Stress-activated Protein Kinase-2 (SAPK2/p38) in the Tumor Cells
J. Biol. Chem.,
August 31, 2001;
276(36):
33762 - 33772.
[Abstract]
[Full Text]
[PDF]
|
 |
|
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